Mounting transistors AND switch question

[Drake120]

I'm making an effect which includes some 2N3904 and MPSA14 transistors. Both of them have 3 leads, as most transistors do :] But my layout shows that I should solder them in four points. The points are signed E, C, B, E. How do I connect it? Should I connect the emitter lead to this second "E"?

Second: switches. Man, that's something I really can't understand when it comes to more complicated switches than DPDT :] So there's my question: I want to have toggle which will "simply" change 4 resistors (for example 4k7, 3k3, 2k2 and 1k) to other four (with other values). But the resistors are not in series and not even "close" to each other. So, according to my understandig, I will need a switch with...24 lugs?

Sorry for my noobism (what a beatiful noun...), but hope you'll help me

[GREEN FUZ]

Some transistors have 4 leads. What are you building?

For your other question, a rotary switch might be appropriate. A schematic or layout would be helpful.

[Drake120]

Oh God. When I was looking for the link to my layout I found a note: "one pad will go unused for each transistor", depending whether the pinout of the transistor is EBC or ECB. Sorry, my fault

The second issue: it was an example. Why do I need a rotary switch if I need only 2 positions (1st position - 1st set of resistors, 2nd pos - 2nd set)? You know, I need some theory and non-specific examples of wiring to understand it, so I could figure these things out by myself in future.But anyway, here's an example which may be useful - http://tonepad.com/getFile.asp?id=81 . How to wire a toggle that will be changing Ra and Rb values (1st position - 100 and 10k, 2nd pos - 470 and 100k)?

Thanks
JS

[ACS]

Think of it this way: switching in sequence - ie first THIS one, then THIS one, then THIS one etc definitely needs a rotary, but importantly only needs a single pole.  Why?  Cos you only ever need one input and one output connected at the same time. 

Switching in parallel (all at the same time) needs one POLE for each item you are switching.  Just think of your standard 3PDT - one pole is switching the input, another the output, and the third the LED.  It just happens to be that this happens at the same time.

So for your example above, you could do it with a 4PDT.  Or a four pole rotary switch.  Rotaries are typically easier to find in multi-pole arrangements.

Hope this helps!
Aidan

[Drake120]

Thanks! Now I'm starting to understand the way it works So now it will be a test for me - I want 3 sets of clipping diodes in a toggle switch. The 6PDT toggle is almost impossible to obtain, so I tried to make it with a 4P3T (on-on-on of course). The circuit is still the Tube Screamer from the link above.



Please don't laugh at me if it's a total crap

Thanks for help
JS

[kurtlives]